Article inventory control systems are used to authorize, track and control movement of items into and out of a facility. An example is a library circulation control system. In this case, each user is uniquely identified by an identification card containing magnetically or optically detectable data (e.g., a barcode). The items to be tracked, books in the collection of the library, for example, have a similar identifying label such that each item is uniquely identified. A computerized database contains identification data on all registered patrons of the library and identification data on all books, videos, audiocassettes, and other items in the library""s collection. When someone desires to remove an item from the library, the library circulation control system first verifies that the person is an authorized patron of the library. The system determines whether the person is authorized to check out any item, or a particular class of items. The system then determines whether the particular item can be removed from the library. Some items which the library may not want removed can include certain reference items, very rare or valuable items, or items that are on reserve. If both the user and the item are authorized by the system, the item may be removed from the library by that user. The system then updates the computerized database to indicate that the particular user has checked out the particular item at issue. The system will also give a visual or audible indication to the user that the item has been checked out, or will give an error message if either the user or the item was not authorized.
To prevent unauthorized removal of items from the facility, electronic article surveillance systems (EAS) may be employed. An EAS system usually includes an EAS marker attached to the items to be protected, a mechanism for interrogating and sensing the marker within an interrogation zone, usually located near the exit of the facility, and a mechanism for preventing unauthorized removal of the article from the facility, such as a locking exit gate or an audible alarm. When an active marker is detected within the interrogation zone, the gate is locked or the alarm is sounded, thus reducing the number of unauthorized removals from the facility.
To allow authorized removal of articles from a facility, dual status markers have been developed. The dual status markers can be deactivated to allow authorized removal, such as check out from a library or video rental store, when the item is returned, the marker c an be reactivated. However, the relatively large magnetic fields required to deactivate the markers is more than sufficient to degrade the prerecorded magnetic signals on audio or video cassettes to a degree that is audibly or visually perceptible by human beings. Such effects, including print through and partial erasure, are highly undesirable.
An apparatus for use in tracking and control of articles out of or into a protected area according to the present invention includes a receiving compartment adapted to receive an article of a plurality of articles. Each of the plurality of articles contains prerecorded magnetic data and further, each article of the plurality of articles has a same predefined configuration with a marker located at a same predetermined position at or near a surface of each article. The receiving compartment is sized and adapted to accept the article in a predetermined orientation within the receiving compartment. The apparatus further includes a magnetic field generating device operable to deactivate the marker and to reactivate the marker by creating a magnetic field proximate the marker without degrading the prerecorded magnetic data of the article.
A method for use in tracking articles out of or into a protected areas according to the present invention includes using a receiving compartment like that of the apparatus summarized above. The method further includes inserting an article having a marker in an activated state into the receiving compartment. It is thereafter sensed whether the article is properly placed within the receiving compartment. The marker of the article in the receiving compartment is then deactivated by creating a magnetic field of sufficient magnitude proximate only the marker. The magnetic field is of a lesser magnitude at a distance from the marker such that the prerecorded magnetic data of the article is not detectably degraded. A method for reactivating a marker in a deactivated state is also provided.